Maximum path sum I
Problem 18
By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top to bottom is 23.
3
7 4
2 4 6
8 5 9 3
That is, 3 + 7 + 4 + 9 = 23.
Find the maximum total from top to bottom of the triangle below:
75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
NOTE: As there are only 16384 routes, it is possible to solve this problem by trying every route. However, Problem
67, is the same challenge with a triangle containing one-hundred rows; it cannot be solved by brute force, and requires a clever method! ;o)
|
||||
Python code:
import math
sqrt=math.sqrt
a=[75,95,64,17,47,82,18,35,87,10,20,4,82,47,65,19,1,23,75,3,34,88,2,77,73,7,63,67,99,65,4,28,6,16,70,92,41,41,26,56,83,40,80,70,33,41,48,72,33,47,32,37,16,94,29,53,71,44,65,25,43,91,52,97,51,14,70,11,33,28,77,73,17,78,39,68,17,57,91,71,52,38,17,14,91,43,58,50,27,29,48,63,66,4,68,89,53,67,30,73,16,69,87,40,31,4,62,98,27,23,9,70,98,73,93,38,53,60,4,23]
k=len(a)
def func(x):
sun=getsun(x)
if sun[1]<k:
return a[x]+max(func(sun[0]),func(sun[1]))
else:
return a[x]
dict={};
def getsun(x):
redult=[];
k=int((sqrt(1+8*x)-1)/2)+1
return [x+k,x+k+1]
print(func(0))
time:<1s